Tension for sewing-machines.



PATNNTED MAY 2'6, 190s. c.- F. da M. T. GQPORTH. TENSION FON SEWING MACHINES.

APPLIUATION FILED JUNE 211,

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TTOR/VEYS UNITED STATES PATENT oEEioE.

CHARLES F. GOFORTH AND MARSHALL T. GOFORTH, OF WICHITA, KANSAS.

f TENSION FOR SEWING-MACHINES.

Speccation of Letters Patent.

Patented May 2e, 190s.

Original application filed November 20, 1906, Serial No. 344,296. Divided and this application led J une 24, 1907.

Serial No.

To all whom it may concern:

Be it known that we, CHARLES F. GOFORTH and MARSHALL T. GOFORTH, citizens of the United States, residing at Wichita, in the county of Sedgwick and State of Kansas, have invented a new and useful Tension for Sewing-Machines, of which the following is a specification.

This invention relates to sewing machines, and has for its principal object to provide a novel form of tension mechanism which may be accurately adjusted and set in accordance with the length of stitches and the thickness of the fabric being operated upon.

A further object of the invention is to provide the tension adjusting mechanism with an indicating means in order to revent change of tension without the know edge of the operator. v

A still further object ofthe invention is to provide a novel form of tension releasing means, so arranged as to release the tension when the presser foot is raised, and to permit the tension mechanism to immediately resume its grasp on the thread when the presser foot is moved down to operative position.

With these and other objects in view, as will more fully hereinafter a pear, the invention consists in certain nove features of construction and arrangement of parts, hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the a pended claims, it being understood that various changes in the form, proportions, size and minor details of the structure may be made without departing from the spirit orsacrificing any of the advanta es of the invention.

In tie accompanying drawings Figure 1 is an end elevation of the head of a sewing machine having a tension mechanism constructed in accordancewith the invention. Fig. 2 is a transverse sectional view of a portion of the same, on the line 2-2 of Fig. 1. Fig. 3 is a similar view on the line 3 3 of Fig. 1. Fig. 4 is a detail sectional view on the line 4-4 of Fig. 1.

Similar numerals of reference are employed to indicate corresponding parts throughout the several figures of the drawings.

This application is a division of an application for Letters Patent filed by us on Novemberno, 1906, Serial N o. 344,296.

Arranged at the end of the gooseneck of ter and receives a compression spring 27, the

stress of which may be adjusted by a nut28 in order to hold the presser foot down with` greater or less force on the fabric. .The presser foot may be raised 'and lowered by means of a-cam lever 29 of ordinary construction. From one side of the presser foot projects a pin 30 that extends through a slot 3l formed in the face plate 32 of the head, this pin being designed to operate the tension device in the manner hereinafter described for the purpose of releasing the tention on the thread when the presser foot is raised, and restoring the tension when the presser foot is lowered to operative position.

On the face plate are arranged two tension plates 46 and 47 the latter plate being slotted to form a curved tongue 48 under which the thread passes, and by which the thread is forced down into engagement with the plate 46. is under the control of a nut 50 and compression spring 51, the nut being mounted on a threaded stem 52 that extends from the face plate and passes through openings in both of the tension plates. The spring surrounds the stem at a point outside the outer plate 47 and fits within a recess formed in the nut. By turning the nut, the stress of the spring may be varied, and the force exerted on the thread may be altered as required. The nut is provided with a pointer 53 arranged to travel over a series of graduations 54 on the outer tension plate, so that the operator may adjust the tension with accuracy.

The outer end of the tension plate 47 is provided with an inbent portion forming a rib 5.6 that is disposed in the path of movement of the pin 30 of the presser foot bar, so that when the presser foot bar is raised and nears the limit of its upward movement, the pin will come into contact with this rib and will force the tension plate outward for the purpose of relieving stress on the thread. When `the presser foot bar is again lowered The tension exerted on the thread to move the presser foot to operative position, the pinleaves the rib 56, and the tension late again exerts its force on the thread.

WE claim:-

l. In a sewing machine, a head having a vertically elongated slot a slotted tension plate having a rib at one end, a presser foot bar, and a pin projecting from the presser foot bar and arranged to engage the rib to relieve the tension as the presser foot bar nears the limit of its upward movement, the pin extending through the slot of the head and being guided hy the Walls of said slot.

2. A sewing machine tension, including a pair of plates, one of which is slotted to form a thread clamping tongue, a screw extend ing through the plates, an adjusting nut mounted on the screw, and a spring arranged vbetween the nut and the outer of said plates,

8. A sewing machine tension including a pair of plates, one of which is slotted to form a thread clam ing tongue, a screw extending through the p ates, an adjusting nut mounted; on the screw, a spring arranged between the nut and the outer of said plates, the nut being provided with an indicator or pointer, and the outer plate having a graduated dial over which the needle or pointer moves to shhw the degree of tension.

In testimony that we claim the foregoing as our own, we have hereto affixed our signatures in the resence of witnesses.

JHARLES F. GOFORTH. MARSHALL T. GOFORTH. Witnesses:

CHAs. G. YANKEY, G. C. WHITLOCK, A. T. HELLAR. 

